This is a note to let you know that I've just added the patch titled wifi: rndis_wlan: Prevent buffer overflow in rndis_query_oid to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: wifi-rndis_wlan-prevent-buffer-overflow-in-rndis_que.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit af82c2653a2995ab03aa8e51ae99485e733c9642 Author: Szymon Heidrich <szymon.heidrich@xxxxxxxxx> Date: Wed Jan 11 18:50:31 2023 +0100 wifi: rndis_wlan: Prevent buffer overflow in rndis_query_oid [ Upstream commit b870e73a56c4cccbec33224233eaf295839f228c ] Since resplen and respoffs are signed integers sufficiently large values of unsigned int len and offset members of RNDIS response will result in negative values of prior variables. This may be utilized to bypass implemented security checks to either extract memory contents by manipulating offset or overflow the data buffer via memcpy by manipulating both offset and len. Additionally assure that sum of resplen and respoffs does not overflow so buffer boundaries are kept. Fixes: 80f8c5b434f9 ("rndis_wlan: copy only useful data from rndis_command respond") Signed-off-by: Szymon Heidrich <szymon.heidrich@xxxxxxxxx> Reviewed-by: Alexander Duyck <alexanderduyck@xxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230111175031.7049-1-szymon.heidrich@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/wireless/rndis_wlan.c b/drivers/net/wireless/rndis_wlan.c index 51e4e92d95a0..0bbeb61ec3a3 100644 --- a/drivers/net/wireless/rndis_wlan.c +++ b/drivers/net/wireless/rndis_wlan.c @@ -712,8 +712,8 @@ static int rndis_query_oid(struct usbnet *dev, u32 oid, void *data, int *len) struct rndis_query *get; struct rndis_query_c *get_c; } u; - int ret, buflen; - int resplen, respoffs, copylen; + int ret; + size_t buflen, resplen, respoffs, copylen; buflen = *len + sizeof(*u.get); if (buflen < CONTROL_BUFFER_SIZE) @@ -748,22 +748,15 @@ static int rndis_query_oid(struct usbnet *dev, u32 oid, void *data, int *len) if (respoffs > buflen) { /* Device returned data offset outside buffer, error. */ - netdev_dbg(dev->net, "%s(%s): received invalid " - "data offset: %d > %d\n", __func__, - oid_to_string(oid), respoffs, buflen); + netdev_dbg(dev->net, + "%s(%s): received invalid data offset: %zu > %zu\n", + __func__, oid_to_string(oid), respoffs, buflen); ret = -EINVAL; goto exit_unlock; } - if ((resplen + respoffs) > buflen) { - /* Device would have returned more data if buffer would - * have been big enough. Copy just the bits that we got. - */ - copylen = buflen - respoffs; - } else { - copylen = resplen; - } + copylen = min(resplen, buflen - respoffs); if (copylen > *len) copylen = *len;